fredrik-fusk.py

import random as r;_,N=range,1e6;l=_(13)*4
print sum([r.shuffle(l)or 0in[x-y for x,y in zip(l[1:],l)]for i in _(N)])/N

fredrik.py

def n(l,p=51):
 if p: return l[p-1]==l[p] or n(l,p-1)
import random as r
S,N=range(13)*4,1e6
a=[0]*int(N)
print map(n,map(lambda a:r.sample(S,52),a)).count(1)/N

jacob.py

n=1e6;i=__import__;l=list("abcdefghijklm"*4);
print len([_ for _ in(i("random").shuffle(l)for _ in range(int(n)))if i("re").search(r"(.)\1","".join(l))])/n

jianhua.c

main(){int N=52,m=1e6,n=0,c=0,x[N],d[N],i,j,k;
while(n++<m){for(i=0;i<N;i++)d[i] = i;for(i=0,j=N;i<N;i++,j--){k=rand()%j;x[i]=d[k];if(i>0&&x[i]%13==x[i-1]%13){c++;break;}else memmove(d+k,d+k+1,4*(j-k-1));}}
printf("%f", 1.* c / m);}

linus.py

import random
l=range(1,14)*4;n=1000000.0
print sum([random.shuffle(l)or 0 in[x-y for x,y in zip(l[1:],l)]and 1or 0for i in range(n)])/n